1. Field of the Invention
The present invention relates to PAC (Physical Access Control), PAC zones, PAC clusters, media containing PAC zones and/or clusters (for example, high density optical discs, such as Blu-ray Disc) and apparatus and methods for recording and/or reproducing data to and/or from the media.
2. Discussion of the Related Art
Media, for example, optical discs may be used for recording a large quantity of data. Of the optical discs available, a new high density optical media (HD-DVD), for example, the Blu-ray Disc (hereafter called as “BD”) is under development, which enables increased recording and/or storing of high definition video and/or audio data.
BD further includes a rewritable Blu-ray disc (BD-RE), Blu-ray disc writable once (BD-WO), and Blu-ray disc read only (BD-ROM).
Currently, one problem with existing systems is the potential incompatibility between drives of different versions, for example a drive of a previous version with a previous set of capabilities may have difficulty interacting with a medium that has interacted with a drive including at least one capability from a subsequent set of capabilities.